Treatment of potentially life-threatening enterovirus infections with pleconaril.

Enteroviruses usually cause self-limited disease that, although associated with high morbidity, is rarely fatal. In certain patient populations, however, the enteroviruses may cause potentially life-threatening infections. Pleconaril is a novel compound that integrates into the capsid of picornaviruses, including enteroviruses and rhinoviruses, preventing the virus from attaching to cellular receptors and uncoating to release RNA into the cell. Pleconaril was used on a compassionate-release basis to treat patients with potentially life-threatening enterovirus infections, and for 38 of these patients sufficient follow-up data were available for determining responses to therapy. Response was evaluated in 4 categories: clinical, virological, laboratory, and radiological. Most patients (28 [78%] of 36), including 12 of 16 with chronic enterovirus meningoencephalitis, were judged to have a clinical response temporally associated with pleconaril therapy. Similarly, nearly all patients whose virological responses (12 [92%] of 13), laboratory responses (14 [88%] of 16), and radiological responses (3 [60%] of 5) could be evaluated were judged to have responded favorably to a course of pleconaril treatment. Adverse effects were minimal and the drug was generally well-tolerated.

Viral meningitis.

Enteroviruses account for 85 to 95% of all cases of aseptic meningitis, but the arboviruses and herpes simplex virus are also important etiologic agents. Mumps, lymphocytic choriomeningitis virus, herpes zoster, human herpesvirus type 6, and influenza viruses are rare causes of meningitis. The virology, pathogenesis, epidemiology, clinical manifestations, diagnostic studies, and established and potential antiviral therapies for viral meningitis are discussed. A differential diagnosis of the aseptic meningitis syndrome is provided.

Picornavirus infections: a primer for the practitioner.

Picornaviruses, including the rhinoviruses and enteroviruses, are common causes of infections in the developed world and the most common reason for prescribing antibiotics. These ubiquitous pathogens are increasingly being recognized in more serious illnesses, such as sinusitis, exacerbations of asthma, exacerbations of cystic fibrosis, myocarditis, meningitis, and severe neonatal sepsislike disease. Recent advances have improved our ability to diagnosis and treat these infections.

Antiviral therapy for enteroviruses and rhinoviruses.

The picornaviruses are a diverse group of viral pathogens that together comprise the most common causes of infection of humans in the developed world. Within the picornavirus family are three well-known groups of human pathogens--the rhinoviruses, the enteroviruses (including polioviruses, coxsackieviruses and echoviruses) and the hepatoviruses (including hepatitis A virus). This article will focus on the rhinoviruses and enteroviruses, agents for which substantial effort has been expended, and recent successes reported, toward the development of safe and effective antiviral therapy.

Stable enterovirus 5' nontranslated region over a 7-year period in a patient with agammaglobulinemia and chronic infection.

Cerebrospinal fluid samples obtained 7 years apart from a patient with chronic meningoencephalitis and underlying agammaglobulinemia were examined to determine enteroviral genotypic variability. From each sample, amplicons spanning 496 nucleotides within the 5' nontranslated region were generated directly from the cerebrospinal fluid and analyzed. A consensus sequence derived from 3 clones of each amplicon revealed only 7 nucleotide changes over the 7-year period within the region studied. The observed 5' nontranslated region mutation rate in this patient ( approximately 0.2% per year) was significantly lower than mutation rates reported for the poliovirus genome.

Clinical significance of enteroviruses in serious summer febrile illnesses of children.

BACKGROUND: Enteroviruses are common causes of aseptic meningitis and nonspecific febrile illnesses in young children. During the summer-fall months, enterovirus-infected children are frequently evaluated in emergency room settings to rule out bacterial sepsis and/or meningitis. OBJECTIVES: We sought to determine the clinical significance of enterovirus infections in children evaluated for serious febrile illnesses in pediatric emergency rooms during the summer-fall season. METHODS: Children admitted to emergency rooms at four university teaching hospitals during a single summer-fall season who required blood culture and/or lumbar puncture to rule out bacterial sepsis/meningitis were prospectively studied. An extensive questionnaire was administered, and specimens of cerebrospinal fluid, serum, urine and throat were tested for enteroviruses by viral culture and PCR. Patients were followed to determine the duration, management and outcome of their illnesses. RESULTS: Of 203 patients studied 173 had no apparent explanation for their illness (e.g. bacterial sepsis, bacterial urinary tract infection, etc.). Of those 173 patients 79 (46%) were infected with enteroviruses, including 33 of 47 (70%) patients with aseptic meningitis, 13 of 25 (52%) patients with nonspecific febrile episodes and 33 of 101 (33%) patients with fever and focal findings (P < 0.0001 for aseptic meningitis vs. fever and focal findings; P = 0.0001 for aseptic meningitis vs. combined nonspecific febrile episodes and fever/focal patients). Among 119 hospitalized patients 65 (55%) were enterovirus-infected. Children < or =90 days of age were more likely to be enterovirus-infected (66 of 122; 54%) than children older than 90 days (13 of 51; 25%) (P = 0.0001). Enterovirus-infected children were more likely to be hospitalized as a result of the current emergency room visit (65 of 79 vs. 54 of 94; P = 0.0005) and were more likely to have had an additional hospitalization for the same illness (10 of 79 vs. 1 of 94; P = 0.003). Enterovirus-infected patients also had a shorter period from illness onset to presentation. Enterovirus-infected children were indistinguishable from those without enterovirus infection in their symptoms at onset, signs at presentation and total duration of illness (>7 days in both groups). Enterovirus-infected children were almost all treated with antibiotics (78 of 79; 99%), with 74 of 79 (94%) receiving parenteral antibiotics for a mean of 3.6 days. CONCLUSIONS: During the summer-fall months, 39% (79 of 203) of children for whom blood cultures and/or lumbar punctures were performed for suspected bacterial infection had enterovirus infection identified as the only explanation for their illness. Of those patients with no alternative diagnosis, enterovirus infection was confirmed in 46% (79 of 179). The majority of those patients requiring hospitalization were infected with enteroviruses. The use of PCR increases the number of children for whom a specific etiology of illness can be determined and may in the future reduce the hospitalization and use of unnecessary antibiotics in patients with enterovirus infections.

Enteroviral meningoencephalitis as a complication of X-linked hyper IgM syndrome.

We describe 5 children from 2 families with mutations in the CD40 ligand (CD40L) gene leading to absent expression of CD40L on activated CD4 cells. All subjects presented with interstitial pneumonia with low serum IgG and normal serum IgM. One child had normal and one child had elevated serum IgA. Four had confirmed Pneumocystis carinii pneumonia. In spite of intravenous immunoglobulin treatment yielding therapeutic serum immunoglobulin levels, 3 children had enteroviral encephalitis. When assessed by flow cytometry, the 3 surviving affected male children had absent CD40L expression on activated CD4(+) T cells. The affected children from both families were shown to have the same single nucleotide insertion (codon 131) resulting in frameshift and early termination within exon 4 (extracellular domain). This observation demonstrates that persistent enteroviral infection is not only observed in X-linked agammaglobulinemia but may also occur in patients with X-linked hyper IgM syndrome.

Clinical and economic impact of enterovirus illness in private pediatric practice.

OBJECTIVE: To characterize the acute clinical course and economic burden of nonpolio enteroviral (NPEV) illness in the summer/fall season as seen in private pediatric practice. METHODS: We prospectively studied 380 children aged 4 to 18 years with systemic NPEV syndromes presenting to private suburban pediatric practices. Seventy-three asymptomatic controls were concurrently enrolled. Clinical diagnosis of NPEV illness was based on the presence of fever plus at least one of the following: headache and stiff neck (n = 2); myalgia and malaise (n = 105); nonpuritic maculopapular rash (n = 10); papulovesicular stomatitis (n = 214); papular rash of the hands, feet, and mouth (H/F/M) (n = 30); or pleurodynia (n = 11). Study participants were enrolled during a 4-month time span (July-October, 1994) and followed daily for 14 days. A parent symptom diary card and twice weekly phone contacts by study nurses characterized the illness to include the frequency of health care contacts, the necessity for laboratory tests, medication use, and school/work absenteeism. RESULTS: Three hundred seventy-two (98%) children completed the study; 122 (33%) of the patients were confirmed to be infected with NPEV. Confirmed NPEV infection was more frequently observed in Rochester, NY (85/147 = 58%) than in Scottsdale, AZ (32/224 = 14%). The age group 4 to 12 years comprised 79% to 90% of the enrollees, depending on the syndrome. Median duration of illness and median number of missed days of school/summer camp/work for the enrolled patients was: meningitis (7 days ill, 2 days missed), myalgia/malaise (9 days ill, 3 days missed), rash (6 days ill, 4 days missed), stomatitis (7 days ill, 2 days missed), H/F/M (7 days ill, 1 day missed), and pleurodynia (8 days ill, 3 days missed). Direct medical costs varied from $69 per case to $771 per case and indirect costs, attributable primarily to parent missed work and/or sick-child care, varied from $63 per case to $422 per case for H/F/M and meningitis, respectively. In households, H/F/M spread to 50% of siblings and 25% of parents. CONCLUSIONS: In our study population, NPEV infection: 1) caused sufficient illness to prompt physician visits in summer and fall; 2) occurred more frequently in 4 to 12 year olds than in adolescents; 3) produced various clinical syndromes concurrently during the same months in the same season of a given year; 4) varied in occurrence geographically; 5) was characterized by numerous symptoms of longer duration than previously recognized; and 6) produced a significant economic impact by generating both direct and indirect costs.

Adverse effects of maternal enterovirus infection on the fetus and placenta.

Gestational outcome in a murine model of congenital enterovirus infection was evaluated. Pregnant mice were inoculated intravenously with Theiler's murine encephalomyelitis virus (TMEV), a murine enterovirus, or with BHK 21 cell lysate (control) at 6-7 days of gestation (early) and sacrificed 6 or 12 days later, and their placentas and fetuses were studied. High rates of gross and histologic abnormalities (50%-87%) were seen in placentas and fetuses from dams infected with TMEV and sacrificed 6 days later. TMEV-infected dams sacrificed 12 days after inoculation had lower rates of placental-fetal abnormalities (25%-57%) but an additional 42% rate of complete pregnancy loss. Pregnancy loss (9%) and placental-fetal abnormalities (4%-7%) were uncommon in control animals. Rates of fetal abnormalities and placental infection in infected dams exceeded fetal viral infection, suggesting that TMEV infection adversely affects pregnancy either directly by fetal damage or indirectly by placental compromise.

Reproducibility of AMPLICOR enterovirus PCR test results.

The reproducibility of AMPLICOR enterovirus PCR test results was determined with clinical samples of cerebrospinal fluid, serum, urine, and throat and rectal swabs. Among 608 samples from which duplicate aliquots were run simultaneously, only seven pairs gave discordant results. Among 104 samples from which duplicate aliquots were run in separate assays, no discordance was seen. Overall, the reproducibility of test kit results was 99% (705 of 712).

Neonatal enterovirus infection: virology, serology, and effects of intravenous immune globulin.

A prospective study of the virology of and serological responses to enterovirus infection in 16 neonates (< or = 2 weeks of life) and their mothers was performed. At study entry, 11 neonates did not have detectable serum neutralizing antibody to their own viral isolates, despite the presence of neutralizing antibody in 9 of 11 mothers of these infants. Viremia and viruria were demonstrated in 8 and 7 neonates, respectively, with maximal detected titers of 6.3 x 10(3) 50% tissue culture infective dose per mL (TCID50) and 6.8 x 10(1) TCID50/mL, respectively. Viremia was associated with onset of illness in the first 5 days of life, low initial serum neutralization titer, and the presence of echovirus serotypes. Randomized administration of intravenous immune globulin (IVIG; 750 mg/kg) to nine neonates overall modestly increased serum neutralization titers but did not reduce the daily incidence of viremia and viruria compared with that of controls. However, receipt of IVIG containing a neutralization titer of > or = 1:800 to the patients' own viral isolates was associated with significantly higher serum neutralization titers and more rapid cessation of viremia and viruria. Future trials of IVIG for neonatal enterovirus disease should assess the efficacy and safety of higher or repeated doses of this agent and/or of IVIG selected for their high titers to frequently circulating and/or particularly virulent enterovirus serotypes.

Enteroviral infections of the central nervous system.

Infections of the CNS with the nonpolio enteroviruses are common and important causes of morbidity in both children and adults. Studies have recently defined the short-term and long-term outcomes of aseptic meningitis due to the enteroviruses. Focal encephalitis is increasingly recognized as a complication of enterovirus infection. Patients at greatest risk for sequelae of CNS enteroviral disease include neonates and those who are immunocompromised. The clinical presentation may mimic that of bacterial or other viral CNS infections, a circumstance making laboratory diagnosis of paramount importance for reducing unnecessary hospitalization and therapy. Recent advances in PCR technology, including its adaptation to a colorimetric microwell plate format, promise to greatly facilitate diagnosis of enteroviral infections. Promising antiviral drugs for CNS disease and other serious manifestations of enteroviral infections are under development.